1. Technical Field
The present invention relates to disposable lighters and more particularly to such lighters which present increased difficulty of operation by unintended users.
2. Background Art
Disposable lighters are available in a variety of forms. One typically common element of disposable lighters is an actuator pad used to release fuel from a reservoir in the lighter. The actuator pad may be used in conjunction with a spark-producing mechanism so that the fuel is ignited soon after it is released. For example, lighters employing conventional spark wheels require a user to rotate a toothed spark wheel against a flint in order to generate a spark. The user then depresses the actuator pad to release and ignite the fuel.
Instead of using a spark wheel, some disposable lighters use piezoelectric mechanisms to generate a spark. In this type of ignition mechanism, a piezoelectric element, such as crystal, is struck by a plexor in order to produce an electric spark where the fuel is released from the lighter. An example of such a piezoelectric ignition mechanism is disclosed in U.S. Pat. No. 5,262,697, entitled “Piezoelectric Mechanism for Gas Lighters.” Typically, actuator pads for disposable lighters using piezoelectric elements are configured and sized to both release fuel and generate a spark so that a user need only push the actuator pad to operate the lighter.
Lighters have been developed to resist undesired operation by unintended users. One typical response is to provide a latch which inhibits inadvertent activation of the actuator pad and makes operation of the lighter more difficult for unintended users. Examples of such latches are illustrated in U.S. Pat. Nos. 6,077,070; 6,022,211; 5,885,069 and 5,228,849. The latches in U.S. Pat. Nos. 6,022,211; 5,885,069 and 5,228,849 are made of a plastic material formed integrally with the actuator pad so that it interferes with the lighter housing to block the actuator pad from being depressed but also permits the latch to be moved inwards into a non-interfering position which allows the actuator pad to be depressed. FIGS. 1a-1c illustrate such a latch in various stages of operation from an initial blocking position (FIG. 1a), a ready or non-blocking position (FIG. 1b), and an actuated position (FIG. 1c).
As shown in FIG. 1a, when the lighter is not in use and the latch is in its initial position, a stop on the outer portion of the latch is positioned in an interfering or blocking relationship with the housing of the lighter to reduce the chance of inadvertent operation of the lighter. In this regard, the latch may be assembled in the lighter in a manner such that it is preloaded and biased into the blocked position. Operation of the lighter thus requires a user to first move the stop on the latch out of interference with the housing by pressing the latch member inwardly. (See FIG. 1b). The latch member bends at its connection to the actuator pad until the latch member contacts a catch mechanism that holds the latch member in order to keep the stop from interfering with the housing. Once the latch member is held by the catch mechanism, the user no longer needs to press the latch to keep it from interfering with the housing. Thus, the user is free to operate the lighter by activating the actuator pad. (See FIG. 1c). The latch member is released from the catch mechanism during motion of the actuator pad so that when the actuator pad returns to its initial position, the latch member returns to its initial blocking position. Over time, the ability of the latch member to return to its initial blocking position may be diminished as shown in FIG. 1d. It is desirable for the latch member to return to its blocking position repeatedly over the life of the lighter and with consistent latch force.